Shower heads in which the direction of hot or cold water spouted from a spouting port changes in an oscillating manner are known. In spout apparatuses such as these shower heads, a nozzle is driven in an oscillating manner by the supply force of supplied water, causing the direction of hot or cold water spouted from a spouting port to change. In this type of spout apparatus, hot or cold water can be jetted from a single spouting port over a wide area, enabling the achievement in a compact constitution of a spout apparatus capable of spouting over a wide range.
At the same time, a warm water flush toilet seat apparatus is presented in Japanese Published Unexamined Patent Application 2000-120141 (Patent Document 1). In this warm water flush toilet seat apparatus, a self-oscillation is induced by a fluidic element nozzle, thus changing the direction in which flush water is jetted. Specifically, in this warm water flush toilet seat apparatus, as shown in FIG. 10, feedback flow paths 104 are provided on both sides of the spray nozzle 102. Each of the feedback flow paths 104 is a loop-shaped flow path communicating with the spray nozzle 102, and a portion of the flush water flowing through the spray nozzle 102 flows in and circulates therein. The spray nozzle 102 is shaped to widen in a tapered form toward a spray port 102a having an elliptical cross section.
When flush water is supplied, the flush water sprayed from spray nozzle 102 is drawn by the Coanda effect to the wall surface on one side or the other of the elliptical cross section spray port 102a and sprayed so as to follow this wall (state “a” in FIG. 10). When flush water is sprayed along one of the wall surfaces, the flush water also flows into the feedback flowpath 104 on the side on which the flush water is being sprayed, and pressure inside the feedback flowpath 104 rises. Due to the rise in pressure, sprayed flush water is pushed, flush water is drawn to the wall surface on the opposite side and sprayed along the wall surface on the opposite side (FIG. 10, state “a”→“b”→“c”). In addition, when flush water is sprayed along the opposite side wall surface, the pressure now rises in the feedback flowpath 104 on the opposite side, and sprayed flush water is pushed back (FIG. 10, state “c”→“b”→“a”). By repetition of this action, sprayed flush water changes direction in an oscillating manner between states “a” and “c” in FIG. 10.
A pure fluidic element is set forth in Japanese Published Unexamined Patent Application 2004-275985 (Patent Document 2). In this pure fluidic element, a linking duct which traverses the fluid jet nozzle is provided; the operation of this linking duct causes an alternating rise in pressure on the upper and lower sides of the fluid jet nozzle. Due to the Coanda effect, the jet current pushed by this pressure rise becomes a jet current along the top plate of the spray jet nozzle, or along the bottom plate thereof; these states are repeated at a certain cycle, becoming a flow in which the spray direction changes in an oscillating manner.
In addition, an oscillating spray apparatus is set forth in Japanese Published Examined Patent Application S.58-49300 (Patent Document 3). This oscillating spray apparatus has the constitution shown in FIG. 11; by using the Karman vortex produced inside an anterior chamber 110, the direction of the jet flow sprayed from an outlet 112 is changed in an oscillating manner. First, a fluid which has flowed into the anterior chamber 110 from an intake port 114 collides with a triangular cross section obstacle 116 placed in an island formation inside the anterior chamber 110. Upon fluid collision, a Karman vortex is alternately produced downstream of the obstacle 116 on the upper and lower sides of the obstacle 116, forming a vortex street.
This Karman vortex street reaches outlet 112 as it grows. Close to the outlet 112, the flow velocity on the side where the vortex street vortex is present speeds up, whereas the flow velocity on the opposite side slows. In the example shown in FIG. 11, Karman vortexes are alternately created on the upper and lower sides of the obstacle 116, and this vortex street sequentially reaches up to the outlet 112, therefore a high flow velocity state is alternately produced on the upper and lower sides in the vicinity of the outlet 112. In the state of high velocity flow on the upper side, the fluid in a high flow velocity state collides with a wall surface 110a on the upper side of the outlet 112 and its direction is changed, whereas the fluid sprayed from the outlet 112 becomes a jet flow which in total is directed diagonally downward. On the other hand in the state of high velocity flow on the lower side, the fluid in a high flow velocity state collides with a wall surface 110b on the lower side of the outlet 112, and a jet flow is sprayed from the outlet 112 in a diagonally upward direction. The alternating repetition of these states results in a reciprocating oscillation during spraying from the outlet 112.
As described above, a system can be conceived in which the fluidic element set forth in Patent Documents 1 through 3 is applied to a spout apparatus such as a shower head, and hot or cold water is discharged as it is oscillates in a reciprocating motion.